At the present time there is very little known about the adaptability of Burn-patients in the early, intermediate and late stages of healing to environmental and exercise stress. Shunting of blood to the wounds in the skin results in high resting cardiac outputs, large cutaneous water loss, increased metabolism and evaporative heat loss with possible changes in thermal stresses and physical work performance in early stages, while later changes in vasomotor control and sweating may be predominant factors. The objective of the proposed investigation is to provide information and guidelines on environmental and work stress limitations in patients who have impaired cutaneous function as a results of extensive and deep burn trauma. Emphasis will be placed on three physiological systems: 1. Metabolism. 2. Thermoregulation. 3. Fluid and Electrolytes. Patients with various degrees of thermally injured cutaneous tissue will be exposed at different times during and after epithelialization to a variety of combinations of thermal and exercise stress. Measurements of O2 consumption, ventilation, heart rate, deep and superficial body temperatures combined with analyses of fluid and electrolyte shifts during and after the periods of imposed stress will be compared with response from a matched group of normal control subjects. While the intermediate and late-stage burn patients will be exposed to environmental and work stresses in the completed new climate unit of the St. Louis University School of Medicine, the stress tolerance of early-phase burn recovery will have to be studied in a climate chamber to be constructed as an annex to the Burn Unit in St. John's Mercy Medical Center. By taking into account factors like time after injury, age, sex, obesity, we hope to provide standards for environmental treatment conditions and for living and working conditions in humans disabled through burn trauma and to study the effects and responses of physical exercise during the whole rehabilitative period.